Gran Bosco di Salbertrand Park covers 3,775 ha, from the 1,000m of the valley bottom to the 2,600m of the watershed with Val Chisone, in the Municipalities of Chiomonte, Exilles, Oulx, Salbertrand, Sauze d'Oulx, Pragelato, and Usseaux. Modern tourist resorts alternate with traditional mountain villages, where nature is still authentic and the centuries-old presence of man is tangible. The fortifications of Assietta and Exilles are only a few examples of the local history which you can find in the books, but on the spot you will find everywhere the evident traces left by the work of man, evidences of centuries of resource exploitation and of the sacrifices of the poor people. An example is the Trou de Touilles, a unique hydraulic work, a gallery at 2,000m built in eight long years, from 1526, by Colombano Romean, a stonecutter from Ramats, who has become for Upper Susa Valley the character symbol of hard work in the mountains.
The Park Authority has been dealing for over thirty years with the safeguard of the environment, but also with the enhancement of the rich local heritage of material and immaterial culture and, since 1996, it has been managing Colombano Romean Ecomuseum - work and tradition in Susa Upper Valley, not a mere museum, but a route-discovery developing between the village of Salbertrand and the protected area that would like to be an instrument of research, evidence of the historical memory and the traditions, and territorial development.
Along a ring-route of about 7 km (walking time: about 2 hours), ancient buildings, structures, and tools used in everyday life are presented to the visitors as examples of a past which can be rediscovered. The 19th-century ice house, the water mill, the oven, the charcoal pile, the Parish Church and its treasures, the frescoed chapel of the Annunciation, the site dedicated to the Waldensians Grand Rentrée tell centuries of history and exploitation of the resources of the territory and are demonstration points of production activities carried out with traditional methods.
Hannibal, Julius Caesar, Charlemagne, and General Catinat are only a few of the great commanders who led their troops in Susa Valley. Because of its strategic geographical position with respect to the several passes connecting the valley with the countries beyond the Alps, the fortified structures increased here over the centuries. This happened above all since the 18th century, when Upper Susa Valley and Val Chisone passed under the rule of the Savoia family after bloody battles like the one held at Testa dell'Assietta on 19 July 1747, the decisive battle of the War of the Austrian Succession: on this occasion, there was the need to build structures hindering the access of the French to Turin. After the Unification of Italy and after the relationships with France deteriorated in the late 19th century, the works for the fortification of the area were resumed. On the contrary, World War I led to a gradual dismantling of the structures, and the main defensive lines were moved to the Austrian front. However, the fortification of the border started again with the rise of Fascism and the building of the so-called "Vallo Alpino".